The parathyroid hormone produced by the principal/chief cells of the parathyroid is a hypercalcemic hormone, It is also called the parathormone. The function of this hormone is to maintain calcium and phosphate balance in the blood and other tissues. It increases calcium reabsorption from the intestine as well as from the nephrons of the kidney. It also initiates bone resorption (e.g. reabsorption of calcium from bones), in case the of low blood calcium levels.